Page 9 - Clinical Connections - Spring 2022

Internal Medicine
FELINE INFECTIOUS PERITONITIS
TREATMENT WITH REMDESIVIR

erlin, a 24-week-old male neutered revealed mild hypoalbuminemia and Treatment and outcome
Bengal cat, was referred to moderate hyperbilirubinemia. Merlin started treatment with 15mg/kg
M the Queen Mother Hospital for Haematological examination revealed remdesivir intravenously. 24 hours later, his
Animals (QMHA) with a one-week history of moderate monocytosis and a marked pleural effusion increased in volume and he
lethargy, hyporexia and a 24-hour history of neutrophilia with left shift and moderate required repeat thoracocentesis. After 36
tachypnoea. toxicity. CT of his thorax and abdomen hours, Merlin remarkably appeared brighter,
He was the first of more than a dozen cats demonstrated bilateral pleural effusion, with he was no longer oxygen-dependent and
with feline infectious peritonitis (FIP) to be pleuritis and multifocal lymphadenopathy. began eating. By 48 hours he was bright,
successfully treated with remdesivir at the Fine needle aspirates of abdominal vocal and active and was transferred out of
RVC. lymph nodes were consistent with the ICU. By 72 hours there was significant
Feline infectious peritonitis is an pyogranulomatous inflammation and the reduction in both pleural and peritoneal
uncommon disease caused by a mutated pleural fluid was a protein-rich transudate effusions.
enteric coronavirus. When diagnosed, the (59g/L) with an A:G ratio of 0.5 and positive By day-five Merlin’s pleural effusion
disease was thought to be almost always coronavirus titre. had resolved, and he was transitioned
fatal due to a lack of efficacious treatment. Merlin’s case was complicated by the onto 10mg/kg subcutaneous remdesivir
Over the past few years, a small number presence of severe phlebitis of his right injections. By day-seven his peritoneal
of studies showed that an antiviral drug cephalic vein from previous catheter effusion had resolved, and he underwent
remdesivir and its parent nucleoside GS- placement, resulting in extensive necrosis a general anaesthetic and surgical repair
441524, could be the key to successfully of the overlying skin. He required skin of his extensive right forelimb wound. He
treating FIP in cats. However, it wasn’t until debridement under general anaesthesia recovered well from the procedure and
the COVID-19 pandemic, when remdesivir and antibiotic treatment. two days later Merlin was discharged to
became licensed to treat COVID-19 While hospitalised, Merlin’s condition complete an 84-day course of subcutaneous
infections in human patients, that the drug unfortunately deteriorated. He developed remdesivir injections at home. His wound
became widely accessible to treat FIP here peritoneal effusion and became recumbent, healed completely with no complications,
in the UK and Australia. obtunded, oxygen-dependent and his pleural and he tolerated his daily remdesivir
On presentation Merlin was pyrexic effusion required repeat thoracocentesis. injections well.
(40oC), with palpable abdominal A diagnosis of FIP was suspected, and It is now several months after Merlin
masses and a pleural effusion requiring his owners opted to start treatment with finished his treatment and he has been
thoracocentesis. Serum biochemistry remdesivir. doing brilliantly at home.
Commenting on Merlin’s case and other
cats treated for FIP at RVC Small Animal
Referrals, Jodie Green and Sarah Tayler,
both of the Internal Medicine Service,
said: “Thirteen cats have now followed in
Merlin’s footsteps and the results have been
astonishing. Cats we were worried were
almost too severely affected have shown
dramatic recoveries within just two to three
days of starting treatment. Six months ago,
we would have considered this a completely
fatal disease and now we’re achieving
treatment success rates of over eighty
percent.
“After Merlin finished his treatment a
new drug in the form of a tablet became
available (GS-441524). This appears to be
just as effective as remdesivir and negates
the need for daily subcutaneous injections.
After initial intravenous remdesivir therapy,
we have transitioned cats onto the oral
tablet with equal success.”
Merlin, the first of several cats treated by remdesivir at the RVC
For small animal referrals, please call:
01707 666399
Email:
qmhreception@rvc.ac.uk

Spring 2022 9